Cartesian coupled coherent states simulations: NenBr2 dissociation as a test case

Abstract

In this article, we describe coupled coherent states (CCS) simulations of vibrational predissociation of weakly bounded complexes. The CCS method is implemented in the Cartesian frame in a manner that is similar to classical molecular dynamics. The calculated lifetimes of the vibrationally excited Ne-Br(2)(ν) complexes agree with experiment and previous calculations. Although the CCS method is, in principle, a fully quantum approach, in practice it typically becomes a semiclassical technique at long times. This is especially true following dissociation events. Consequently, it is very difficult to converge the quantum calculations of the final Br(2) vibrational distributions after predissociation and of the autocorrelation functions. However, the main advantage of the method is that it can be applied with relative ease to determine the lifetimes of larger complexes and, in order to demonstrate this, preliminary results for tetra- and penta-atomic clusters are reported.

Quantum dynamics with fermion coupled coherent states: Theory and application to electron dynamics in laser fields

“…The method of coupled coherent states (CCS) [1][2][3][4][5][6][7][8][9][10][11][12][13] has been developed previously to provide a tool for fully quantum simulation of systems with a large number of degrees of freedom. The central idea of the technique is to solve the time-dependent Schrödinger equation in a basis of frozen (i.e.…”

“…Second, the trajectory-guided basis follows the evolution of the wave function, and thus it further economizes the basis set size and computational cost. The CCS method and its variations [14,15] has been applied successfully to a number of problems, which require simulation of quantum dynamics in complex multidimensional systems, such as vibrational energy transfer [4,12], nonadiabatic dynamics in molecules [14,15], dynamics and spectra of small clusters [5,13], and tunneling in systems with many degrees of freedom [8].…”

Quasi-classical trajectories study of Ne2Br2(B) vibrational predissociation: Kinetics and product distributions

“…The interested reader is referred to Ref. 49 which not only describes in detail our previous work on the VP of NeBr 2 but also outlines the extension to larger clusters. A more detailed CCCS study of Ne 2 Br 2 will be published in due course 69 .…”

“…In our previous work 49 , we found that the basis functions in the simulations of the VP of NeBr 2 remained coupled until the clusters completely dissociate. In the current work, however, the basis functions decouple much more quickly due to the increased dimension of phase space.…”

“…In this paper, we report QCT and preliminary Cartesian coupled coherent states (CCCS) 48,49 calculations on the VP of Ne 2 Br 2 (B, v ′ = 16-23). We compare both theoretical methods, as well as their ability to reproduce the experimental observations 47 and previous MDQT predictions 11 .…”